Various techniques are known for obtaining an identifier associated with an individual from elements relating to a fingerprint.
One of these techniques described in the article “Fingerprint matching from minutiae texture maps” by F. Benhammadi, M. N. Amirouche, H. Hentous, K. Bey Beghdad and M. Aissani, Pattern Recognition 40 (2007) 189-197, seems particularly interesting.
It provides for the determination of a fixed identifier on the basis of the image of a fingerprint, by extracting from it the minutiae, i.e. the irregularities on the ridge lines of this print, such as the ridge endings and the bifurcations, then by applying Gabor filters to the texture of the fingerprint locally, around each of the extracted minutiae.
Unlike the techniques of the prior art where the identifier resulted from the application of Gabor filters around a morphological core which was not always present or detectable within the fingerprint image, an identifier according to the above-mentioned article can always be obtained, as it is always possible to identify minutiae within the fingerprint image.
The identifier obtained according to this article moreover offers a greater robustness with regard to geometrical transformations which can impact on the fingerprint image, such as translations and/or rotations, since each of the Gabor filters is chosen taking account of the orientation of the minutia around which it is applied.
The technique described in this article however requires full prior knowledge of the image of a fingerprint. This can pose a problem in practice, as most of the current biometric databases do not store such images, but only characteristics relating to the minutiae, as is furthermore required by standard ISO/IEC 19794-2:2005 “Information technology—Biometric data interchange formats—Part 2: Finger minutiae data”.
Moreover, the comparison of identifiers determined according to the above-mentioned article “Fingerprint matching from minutiae texture maps” gives less than optimal results, in that it does not take account of certain local specificities of the corresponding fingerprint images, such as their quality or their relevance.